Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
School of Environmental Sciences, University of Liverpool, Liverpool, UK.
Nat Commun. 2020 Apr 2;11(1):1627. doi: 10.1038/s41467-020-15511-6.
Inland waters (rivers, lakes and ponds) are important conduits for the emission of terrestrial carbon in Arctic permafrost landscapes. These emissions are driven by turnover of contemporary terrestrial carbon and additional pre-aged (Holocene and late-Pleistocene) carbon released from thawing permafrost soils, but the magnitude of these source contributions to total inland water carbon fluxes remains unknown. Here we present unique simultaneous radiocarbon age measurements of inland water CO, CH and dissolved and particulate organic carbon in northeast Siberia during summer. We show that >80% of total inland water carbon was contemporary in age, but pre-aged carbon contributed >50% at sites strongly affected by permafrost thaw. CO and CH were younger than dissolved and particulate organic carbon, suggesting emissions were primarily fuelled by contemporary carbon decomposition. Our findings reveal that inland water carbon emissions from permafrost landscapes may be more sensitive to changes in contemporary carbon turnover than the release of pre-aged carbon from thawing permafrost.
内陆水域（河流、湖泊和池塘）是北极永冻景观中陆地碳排放的重要渠道。这些排放是由当代陆地碳的周转和从解冻永冻土中释放的额外预龄（全新世和更新世晚期）碳驱动的，但这些源对总内陆水碳通量的贡献程度尚不清楚。在这里，我们在夏季同时提供了西伯利亚东北部内陆水 CO、CH 以及溶解和颗粒有机碳的独特放射性碳年龄测量结果。我们表明，>80%的内陆水总碳具有现代年龄，但在受永冻土融化强烈影响的地点，预龄碳的贡献>50%。CO 和 CH 比溶解和颗粒有机碳年轻，表明排放主要由当代碳分解提供燃料。我们的研究结果表明，与解冻永冻土释放预龄碳相比，内陆水碳排放可能对当代碳周转变化更为敏感。
